OFFSET
1,2
COMMENTS
Parekh et al. conjecture that q^5-q^4 is the number of nonsingular generalized Weierstrass curves over the field with q elements, for q>1.
LINKS
Param Parekh, Paavan Parekh, Sourav Deb, and Manish K. Gupta, On the Classification of Weierstrass Elliptic Curves over Z_n, arXiv:2310.11768 [cs.CR], 2023.
PROG
(Python)
from sympy import primepi, integer_nthroot
def A371195(n):
def f(x): return int(n-2+x-sum(primepi(integer_nthroot(x, k)[0]) for k in range(1, x.bit_length())))
kmin, kmax = 1, 2
while f(kmax) >= kmax:
kmax <<= 1
while True:
kmid = kmax+kmin>>1
if f(kmid) < kmid:
kmax = kmid
else:
kmin = kmid
if kmax-kmin <= 1:
break
return kmax**4*(kmax-1) # Chai Wah Wu, Aug 20 2024
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Mar 14 2024
STATUS
approved